A vehicle engine may include an air cooler for cooling the intake air of the engine. The air cooler may be either an air-cooled air cooler using the ambient air as a cooling agent or a water-cooled air cooler using cooling water as a cooling agent. See JP2010-127143A and JP2012-520409A.
Typically, such an air cooler is used for the purpose of lowering the temperature of the intake air which is raised owing to the use of a turbocharger for compressing the intake air. Even in the case of a natural aspiration engine, the intake member defining an intake passage and located in the engine room may be warmed by the heat from the engine (in particular, the exhaust system thereof). In such a case, it may be advantageous to provide an air cooler in order to prevent the intake passage from becoming undesirably high in temperature.
If an air-cooled air cooler is used for such a purpose, the air cooler is required to be positioned near the front grill located in a front part of the vehicle so that the fresh air drawn from outside, instead of the warmed air in the engine room, may be made available. However, the front end part of the engine room is already occupied by other devices of the engine in most cases, and does not provide an adequate space required for placing the air cooler. In the case of a water-cooled air cooler, because of the need for the piping for the cooling water and other component parts, the cost may be unacceptably high.